A significant portion of our population has a certain degree of hearing loss. This can be due to, for example, heredity, noise exposure or simply aging. Hearing aids have been the traditional approach for those with hearing difficulties. However, just in the United States, out of the 26 to 28 million people who are hearing impaired, only about 20% of them actually wear any hearing aids. Further, this number of hearing impaired is steadily increasing. Hearing loss typically goes with aging. With the baby boom population rapidly aging, the median age of the entire population is going up. Significantly more people will be in need of hearing aids.
One main reason for the lack of wide adoption of hearing aids could be that there is still a stigma towards wearing them. Wearing hearing aids is typically linked to old age, and people from many cultures value youthfulness. They do not like to be perceived as being old. As a result, many people with mild or moderate hearing loss just ignore it and live with their deficiencies.
Basically, there are three major types of hearing aids—the “behind-the-ear” (BTE) style, the “in-the-ear” (ITE) style, and the completely-in-the-canal (CIC) style. The BTE hearing aids have a number of advantages. They are more applicable for those with severe hearing loss. Through the use of venting, they reduce to a certain degree the effects of occlusion, which is the hollowness, echoic or stuffed sensation of hearing one's own voice as one talks with a hearing aid inside one's ear. The ITE (or CIC) designs are more inconspicuous. They are located inside the ear. Just like the BTE, individual ear molds are typically made for such hearing aids based on an impression of the user's ear canal. Such custom-made hearing aids can be expensive. But, in certain countries, even with the government paying for such hearing aids, most people still do not like to wear them.
Hearing ability tends to decrease gradually, particularly as we age. A person with mildly-impaired hearing normally does not need the same degree of hearing assistance as one with severely-impaired hearing. Nevertheless, though their hearing loss is not severe, they still could benefit from mild or moderate enhancement to their hearing.
One approach to make the hearing aids not as conspicuous is to add them to eyeglasses, either by affixing them to, or built them into, glasses. However, it may still be obvious to a third party that the person is wearing a hearing aid. Also, it is not easy to have hearing aids attached to or built-into glasses. Eyeglasses frames tend to be very compact and lightweight and thus have little space for electrical components. Moreover, since eyeglass frames are often fashionable items whose designs are important, there are substantial design tradeoffs involved with hearing aids built in or attached to the eyeglass frames.
It should be clear from the foregoing that there is still a need for improved techniques to assist those who are hearing impaired, and there is still a need to improve techniques to bring electrical signals to us through glasses.